Gov. Parris N. Glendening (D) refused yesterday to appoint Larry Young, one of his strongest supporters, to the Maryland Senate. The governor rebuffed Young's effort to regain the seat he lost last month for violating state ethics rules.

Saying that Maryland's constitution and state law prohibited Young from serving in the Senate for the rest of this year, the governor said he would not accept the nomination of Young sent to him this week by Baltimore's 44th District Democratic Central Committee.

The Baltimore Democrats' decision placed Glendening in a difficult political position, forcing him to act against the popular former senator at a time when the governor would like the backing of Young's supporters for his own reelection bid this year.

"Under the law and under the constitution, I cannot make this appointment," Glendening said at a news conference flanked by state Attorney General J. Joseph Curran Jr. (D). Curran's office had offered a written opinion to Baltimore Democrats, advising them that Young was ineligible for the post.

Young expressed disappointment with Glendening's decision last night. He said Glendening and his aides never called to see whether the central committee would consider nominating someone other than Young.

"I thought the governor could have called me and we could have sat down and discussed what was on the table," Young said. "He very well might have persuaded those five members [of the central committee] to consider another option."

In the absence of such an effort, Young said, he decided to seek renomination because he felt it would be best for his district, which he said is his top priority. Young said he was leaving a possible legal challenge of the governor's decision up to the the central committee, whose chairman did not return phone calls yesterday.

Last month, Young became the first state senator in Maryland history to be expelled after the legislature's ethics committee determined that he had abused his office to reap tens of thousands of dollars from companies and agencies with business before state government. Federal and state grand juries are now investigating.

Not wanting to get drawn into the political controversy surrounding Young, Glendening has largely avoided direct criticism of the former senator, although he has said the Senate acted "appropriately." But speaking to reporters yesterday, Glendening said he found Young's actions, as presented in the legislature's ethics committee report, "inappropriate and unacceptable."

"The public has the right to expect the highest level of behavior and has the right to expect an appropriate response. His behavior violated basic ethics," Glendening said.

But he also stressed that his personal opinion of Young's activities did not play a part in his decision. Rather, he said, he was bound by the attorney general's ruling that Young had been expelled "for the remainder of the current four-year term," which ends in January. Had the governor received any other qualified nomination, he would have been legally obliged to appoint that person.

Glendening said he now hoped the Democrats in Baltimore would forward an acceptable candidate for appointment to Young's old seat.

Some Baltimore Democrats said Glendening's decision yesterday will not cause serious political damage in the city, a key part of his political base.

"I'm going to support the governor," said Sen. Nathaniel J. McFadden (D-Baltimore). "That's based on his responsiveness and his keeping his promises to the African American community and Baltimore City. . . . Once those individuals in the 44th District look at the alternatives to this governor, I think it will be clear who their choice should be."

But Glendening and some of his advisers did not hide their unhappiness with having to wade into the racially charged situation. Some black politicians have complained that Young was the subject of a double standard by senators pushing for his expulsion.

Asked whether he wished Young's nomination had not been sent to him, Glendening replied: "Yes, absolutely."

"Does it cause problems? Yes," said Lance W. Billingsley, a political confidant of the governor's. "But is it a bad thing? I'm not sure it necessarily is. The process was allowed to work. Larry Young is very, very popular in his district. [The committee] made a decision out of friendship and loyalty to Larry Young."

Still, it was a dilemma that Glendening and key Democrats did nothing to avert.

Glendening said he never contacted Young or the central committee before Tuesday night's vote, and party leaders did nothing to try to persuade the Baltimore committee members to avoid embarrassing Glendening as he faces a difficult reelection effort.

"The party did not attempt to influence their decision," said Democratic state Chairman Peter Krauser, refusing to elaborate.